This invention relates generally to apparatus for inserting prewound coils and slot wedges into the slots of an internally slotted core of a dynamoelectric machine. The invention is particularly concerned with an improved technique for disassembling a portion of the machine for replacement of the coil turn feeder blades, the wedge guide blades, and/or the wedge pusher blades.
In typical dynamoelectric machines, such as an electric motor, generator, alternator, or the like, the stator assembly comprises a generally cylindrical stack of laminations made from a magnetic material having a plurality of axially extending slots formed in the internal bore thereof. Electrical coils, or more specifically the side turn portions of electrical coils, are then inserted into the slots in various configurations to produce a desired magnetic field for operation of the device. Because the insulation on the conductors forming the electrical coils can be easily damaged during assembly and insertion, and because insertion of the coils into the proper slots is itself a difficult and exacting procedure, there have been developed a variety of complex precision machines for performing these operations. Such machinery includes apparatus for forming and inserting the coils, as well as for inserting the insulators and coil retaining wedges into the stator. Frequently, these machines are combined into a single assembly.
Representative of such machines are those disclosed in U.S. Pat. No. 3,722,063, issued to Richard B. Arnold, U.S. Pat. No. 3,829,953, issued to Richard E. Lauer et al.; U.S. Pat. No. 4,477,966, issued to Reinhard Napierski; U.S. Pat. No. 3,447,255, issued to Robert J. Eminger; U.S. Pat. No. 4,476,625, issued to Robert W. Bricker et al.; and U.S. Pat. No. 4,416,058, issued to Henry, Sr. et al.
A definite disadvantage in such prior art machines exists in the long, thin precision-machined elements, including coil turn feeder blades, wedge guide blades, and wedge pusher blades. In a typical arrangement, a slotted wedge magazine is automatically loaded from a separate machine or assembly which forms the wedges or insulators and inserts them into wedge-receiving slots of the magazine. In the course of loading the wedges into the magazine, the magazine is incrementally rotated or indexed. Subsequently, the wedge pusher blades move axially into the wedge-receiving slots of the magazine to force the wedges or insulators into the appropriate slots of the magnetic core. At this particular stage of operation of the machine, it is essential that the pusher blades be in precise alignment with the wedge-receiving slots of the magazine, the longitudinal passages defined by adjacent wedge guides, and the appropriate slots of the magnetic core. Any misalignment between the pusher blades and these elements can result in damage to, or even destruction of, the pusher blade assembly, the wedge guide blades and/or the coil turn feeder blades.
The problem of misalignment between the pusher blades and the wedge magazine is overcome in accordance with the disclosure of Bricker et al. U.S. Pat. No. 4,476,625, since the pusher blades are at all times received by the slots in the wedge magazine and rotate with the magazine during the wedge insertion sequence. While the patent to Bricker et al. greatly reduced the possibility of damage to the pusher blades, conditions still exist which cause damage to the pusher blades and the other blades described above. These conditions include misalignment of the stator slots, accumulation of tolerances in the relatively movable parts of the machine, distortion of the blades themselves which can occur as a result of use and abuse, and incomplete cycling of the machine.
In some extreme instances, some of the pusher blades and a significant number of wedge guide blades and coil turn feeder blades may be destroyed, but in most instances only a few blades are damaged or destroyed and need to be replaced. In either case, however, it is necessary to disassemble that portion of the apparatus which includes the coil turn feeder blades and the wedge guide blades. This is particularly true if the teachings of the Bricker et al. patent are followed, since the wedge guide blades and the coil turn feeder blades are supported by a collet which radially embraces these elements. According to the construction of the Bricker et al. apparatus, the wedge guide blade retaining collet must be removed in order to remove the wedge guide blades and the radially adjacent coil turn feeder blades. Removal of the collet, however, leaves the entire wedge guide array radially unrestrained. After replacement of a blade, the entire wedge guide and coil turn feeder array must be carefully inspected to ensure that each blade is properly positioned in its proper place with respect to the wire stripper and various supporting notched rings.
A further complication according to prior art assemblies is that the wedge guides are also supported at their proximal ends by an adapter plate and an associated guide ring which necessitates the removal of these elements for removal of the coil turn feeder blades.